This book was the best I could find. It features lots of colorful caricatures the bear on the songs. It's very well suited to a full-size guitar or soprano guitar because it focuses on only the top four strings of the guitar in Book 1.

I also supplement this book with popular songs for kids such as the Theme from Spiderman, Theme from Transformers, and....get this....songs by Elvis Presley that kids seem to love when they hear them (Strange , isn't it!) They also learn folk songs and popular campfire songs and can also learn songs they just like if they are ready for them.